Size distribution of near-surface aerosols and its relation to the columnar aerosol optical depths

Abstract. Simultaneous data on Aerosol Optical Depth (AOD) and size segregated, near-surface, aerosol mass concentration was obtained from a Multi wavelength Solar Radiometer (MWR) and Quartz Crystal Microbalance Impactor (QCM), respectively. These were used to examine the association between near-surface aerosol properties and columnar AOD. The spectral AODs were approximated to the Ångström relation τp=βλ-α, and the wavelength exponent α and turbidity coefficient β have been obtained. In general, α was found to be well associated with the relative abundance of accumulation mode aerosols (estimated from the simultaneous QCM data) while β followed the variations of the coarse mode aerosol mass concentration; the association being closer during periods of continental airmass.

Download Full-text

Vertical distribution of aerosols in the vicinity of Mexico City during MILAGRO-2006 Campaign

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-1017-2010 ◽

2010 ◽

Vol 10 (3) ◽

pp. 1017-1030 ◽

Cited By ~ 21

Author(s):

P. A. Lewandowski ◽

W. E. Eichinger ◽

H. Holder ◽

J. Prueger ◽

J. Wang ◽

...

Keyword(s):

Size Distribution ◽

Mexico City ◽

Mass Concentration ◽

Heavy Traffic ◽

Aerosol Size Distribution ◽

Lidar System ◽

Aerosol Mass ◽

Aerosol Mass Concentration ◽

Lidar Measurements ◽

Ground Based Lidar

Abstract. On 7 March 2006, a mobile, ground-based, vertical pointing, elastic lidar system made a North-South transect through the Mexico City basin. Column averaged, aerosol size distribution (ASD) measurements were made on the ground concurrently with the lidar measurements. The ASD ground measurements allowed calculation of the column averaged mass extinction efficiency (MEE) for the lidar system (1064 nm). The value of column averaged MEE was combined with spatially resolved lidar extinction coefficients to produce total aerosol mass concentration estimates with the resolution of the lidar (1.5 m vertical spatial and 1 s temporal). Airborne ASD measurements from DOE G-1 aircraft made later in the day on 7 March 2006, allowed the evaluation of the assumptions of constant ASD with height and time used for estimating the column averaged MEE. The results showed that the aerosol loading within the basin is about twice what is observed outside of the basin. The total aerosol base concentrations observed in the basin are of the order of 200 μg/m3 and the base levels outside are of the order of 100 μg/m3. The local heavy traffic events can introduce aerosol levels near the ground as high as 900 μg/m3. The article presents the methodology for estimating aerosol mass concentration from mobile, ground-based lidar measurements in combination with aerosol size distribution measurements. An uncertainty analysis of the methodology is also presented.

Download Full-text

Development of a three-dimensional variational assimilation system for lidar profile data based on a size-resolved aerosol model in WRF-Chem model v3.9.1 and its application in PM<sub>2.5</sub> forecasts across China

10.5194/gmd-2020-223 ◽

2020 ◽

Author(s):

Yanfei Liang ◽

Zengliang Zang ◽

Dong Liu ◽

Peng Yan ◽

Yiwen Hu ◽

...

Keyword(s):

Mass Concentration ◽

Three Dimensional ◽

Initial Field ◽

Forecast Performance ◽

Near Surface ◽

Aerosol Model ◽

Aerosol Mass ◽

Aerosol Mass Concentration ◽

Particulate Matter 2.5 ◽

Assimilation System

Abstract. For the aerosol variables in the model for simulating aerosol interactions and chemistry (MOSAIC)-4bin chemical scheme in the Weather Research and Forecasting–Chemistry (WRF–Chem) model, this study presents an observation forward aerosol extinction coefficient (AEC) and aerosol mass concentration (AMC) operator and corresponding adjoint based on the interagency monitoring of protected visual environments (IMPROVE) equation, and then a three-dimensional variational (3-DVAR) data assimilation system (DA) is developed for lidar AECs and AMCs. DA experiments are conducted based on AEC profiles measured by five light detection and ranging (lidar) systems as well as mass concentration (MC) data measured at over 1,500 ground environmental monitoring stations across China for particulate matter 2.5 µm or less in diameter (PM2.5) and PM between 2.5 and 10 µm in diameter (PM10). An experiment comparing assimilated and without assimilated measurements finds the following. While only five lidars were available within the simulation region (approximately 2.33 million km2 in size), assimilating lidar AEC data alone can effectively improve the accuracy of the initial field of the WRF–Chem as well as its forecast performance for PM2.5MCs. Compared to the without assimilated experiment, DA reduces the root mean square error of surface PM2.5MCs in the initial field of the model by 10.5 μg/m3 (17.6 %). Moreover, the positive effect resulting from the optimization of the initial field for AMCs can last for more than 24 h. By taking advantage of lidar aerosol vertical profile information and the near-surface PM MC observations, assimilating lidar AEC and surface PM2.5 (PM10) simultaneously can effectively integrate their observed information and generate a more accurate 3D aerosol analysis field.

Download Full-text

Ground-based in situ measurements of near-surface aerosol mass concentration over Anantapur: Heterogeneity in source impacts

Advances in Atmospheric Sciences ◽

10.1007/s00376-012-1234-5 ◽

2012 ◽

Vol 30 (1) ◽

pp. 235-246 ◽

Cited By ~ 3

Author(s):

B. S. K. Reddy ◽

K. R. Kumar ◽

G. Balakrishnaiah ◽

K. R. Gopal ◽

R. R. Reddy ◽

...

Keyword(s):

Mass Concentration ◽

In Situ Measurements ◽

Near Surface ◽

Aerosol Mass ◽

Aerosol Mass Concentration

Download Full-text

Secondary organic aerosol formation during June 2010 in Central Europe: measurements and modelling studies with a mixed thermodynamic-kinetic approach

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-26761-2013 ◽

2013 ◽

Vol 13 (10) ◽

pp. 26761-26793

Author(s):

B. Langmann ◽

K. Sellegri ◽

E. Freney

Keyword(s):

Organic Carbon ◽

Size Distribution ◽

Atmospheric Chemistry ◽

Mass Concentration ◽

Three Dimensional ◽

Kinetic Approach ◽

Aerosol Formation ◽

Aerosol Mass ◽

Aerosol Mass Concentration ◽

Organic Vapour

Abstract. Until recently secondary organic carbon (SOC) aerosol mass concentrations have been systematically underestimated by three-dimensional atmospheric-chemistry-aerosol models. With a newly proposed concept of aging of organic vapours more realistic model results for organic carbon aerosol mass concentrations could be achieved. Applying a mixed thermodynamic-kinetic approach for SOC aerosol formation shifted the aerosol size distribution towards particles in the cloud condensation nuclei size range, thereby emphasising the importance of SOC aerosol formation schemes for modelling realistic cloud and precipitation formation. The additional importance of hetero-molecular nucleation between H2SO4 and organic vapours remains to be evaluated in three-dimensional atmospheric-chemistry-aerosol models. Here a case study is presented focusing on Puy-de-Dôme, France in June 2010. Even though nucleation events at Puy-de-Dôme were rare during the chosen period of investigation a weak event in the boundary layer could be reproduced by the model when nucleation of low-volatile secondary organic vapour is included. Differences in the model results with and without nucleation of organic vapour are visible in the lower free troposphere over several days of the period. Taking into account nucleation of organic vapour leads to an increase in accumulation mode particles due to coagulation of nucleation and aitken mode particles. Moreover, the measurements indicate a considerable increase in SOC aerosol mass concentration during the measurement campaign, which could be reproduced by modelling using a simplified thermodynamic-kinetic approach for SOC aerosol formation and increased biogenic VOC precursor emissions. Comparison with a thermodynamic SOC aerosol formation approach shows a huge improvement in modelled SOC aerosol mass concentration with the thermodynamic-kinetic approach for SOC aerosol formation and a slight improvement of modelled particle size distribution.

Download Full-text

Influence of the aerosol solar extinction on photochemistry during the 2010 Russian wildfires episode

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-10983-2015 ◽

2015 ◽

Vol 15 (19) ◽

pp. 10983-10998 ◽

Cited By ~ 9

Author(s):

J. C. Péré ◽

B. Bessagnet ◽

V. Pont ◽

M. Mallet ◽

F. Minvielle

Keyword(s):

Transport Model ◽

Regional Scale ◽

Model Performance ◽

Surface Concentration ◽

Near Surface ◽

Aerosol Mass ◽

Aerosol Mass Concentration ◽

Air Quality Measurements ◽

Photolysis Rates ◽

Optical Module

Abstract. In this work, impact of aerosol solar extinction on the photochemistry over eastern Europe during the 2010 wildfires episode is discussed for the period from 5 to 12 August 2010, which coincides to the peak of fire activity. The methodology is based on an online coupling between the chemistry-transport model CHIMERE (extended by an aerosol optical module) and the radiative transfer code TUV. Results of simulations indicate an important influence of the aerosol solar extinction, in terms of intensity and spatial extent, with a reduction of the photolysis rates of NO2 and O3 up to 50 % (in daytime average) along the aerosol plume transport. At a regional scale, these changes in photolysis rates lead to a 3–15 % increase in the NO2 daytime concentration and to an ozone reduction near the surface of 1–12 %. The ozone reduction is shown to occur over the entire boundary layer, where aerosols are located. Also, the total aerosol mass concentration (PM10) is shown to be decreased by 1–2 %, on average during the studied period, caused by a reduced formation of secondary aerosols such as sulfates and secondary organics (4–10 %) when aerosol impact on photolysis rates is included. In terms of model performance, comparisons of simulations with air quality measurements at Moscow indicate that an explicit representation of aerosols interaction with photolysis rates tend to improve the estimation of the near-surface concentration of ozone and nitrogen dioxide as well as the formation of inorganic aerosol species such as ammonium, nitrates and sulfates.

Download Full-text

Aerosol mass concentration measurements: Recent advancements of real-time nano/micro systems

Journal of Aerosol Science ◽

10.1016/j.jaerosci.2017.09.008 ◽

2017 ◽

Vol 114 ◽

pp. 42-54 ◽

Cited By ~ 10

Author(s):

U. Soysal ◽

E. Géhin ◽

E. Algré ◽

B. Berthelot ◽

G. Da ◽

...

Keyword(s):

Real Time ◽

Mass Concentration ◽

Aerosol Mass ◽

Aerosol Mass Concentration ◽

Concentration Measurements ◽

Micro Systems

Download Full-text

Particle size sensitivity of two aerosol mass concentration monitors

AIHAJ ◽

10.1080/15298668291410468 ◽

1982 ◽

Vol 43 (9) ◽

pp. 712-715

Author(s):

C.I. FAIRCHILD

Keyword(s):

Particle Size ◽

Mass Concentration ◽

Aerosol Mass ◽

Aerosol Mass Concentration

Download Full-text

Retrieval of Vertical Mass Concentration Distributions—Vipava Valley Case Study

Remote Sensing ◽

10.3390/rs11020106 ◽

2019 ◽

Vol 11 (2) ◽

pp. 106 ◽

Cited By ~ 5

Author(s):

Longlong Wang ◽

Samo Stanič ◽

Klemen Bergant ◽

William Eichinger ◽

Griša Močnik ◽

...

Keyword(s):

Biomass Burning ◽

Mass Concentration ◽

Mineral Dust ◽

Small Scale ◽

Vertical Profiles ◽

Total Uncertainty ◽

Aerosol Mass ◽

Aerosol Mass Concentration ◽

Aerosol Types

Aerosol vertical profiles are valuable inputs for the evaluation of aerosol transport models, in order to improve the understanding of aerosol pollution ventilation processes which drive the dispersion of pollutants in mountainous regions. With the aim of providing high-accuracy vertical distributions of particle mass concentration for the study of aerosol dispersion in small-scale valleys, vertical profiles of aerosol mass concentration for aerosols from different sources (including Saharan dust and local biomass burning events) were investigated over the Vipava valley, Slovenia, a representative hot-spot for complex mixtures of different aerosol types of both anthropogenic and natural origin. The analysis was based on datasets taken between 1–30 April 2016. In-situ measurements of aerosol size, absorption, and mass concentration were combined with lidar remote sensing, where vertical profiles of aerosol concentration were retrieved. Aerosol samples were characterized by SEM-EDX, to obtain aerosol morphology and chemical composition. Two cases with expected dominant presence of different specific aerosol types (mineral dust and biomass-burning aerosols) show significantly different aerosol properties and distributions within the valley. In the mineral dust case, we observed a decrease of the elevated aerosol layer height and subsequent spreading of mineral dust within the valley, while in the biomass-burning case we observed the lifting of aerosols above the planetary boundary layer (PBL). All uncertainties of size and assumed optical properties, combined, amount to the total uncertainty of aerosol mass concentrations below 30% within the valley. We have also identified the most indicative in-situ parameters for identification of aerosol type.

Download Full-text